How to calculate probability
P = favorable ÷ total · P(at least once in n) = 1 − (1−p)ⁿ
Worked example. Probability per attempt: 16.67%.
Example inputs — Favorable outcomes: 1; Total possible outcomes: 6; Number of attempts: 1. Starting values are illustrative.
From George Guju, founder of Calculyn · Educational calculator guidance, not professional advice.
How it works
Probability is favorable outcomes divided by total outcomes. For repeated independent attempts, the chance of at least one success is 1 − (1 − p)^n.
Assumptions & limitations
- Results are rounded for display.
Formula and assumptions reviewed October 2026 by the Calculyn team. How we build our calculators
Frequently asked questions
Does each attempt change the odds?
Only if outcomes aren't replaced (like drawing cards without putting them back). This calculator assumes independent attempts.